ar15.com has frequent discussions on the F-22 but nothing quite as simple as this
You dont get to be the best and stay the best by sitting on your ass.
Everyday someone else is having an idea, or making a technology, whether or not they can act on it or do something with it really isnt of consequence. Right now, we have the world's foremost aerospace industry, we have the money, so we are building the planes. There is absolutely no way to predict what is going to happen in the next 20-30 years (life-cycle of the last generation of military planes).
The only question should be, is this the absolute best plane we can build?